In general, among conventional methods of diagnosing and processing a failure which may occur in various electronic devices or network equipments at home or in a building, most methods analyze system logs or failure occurrence messages to find the cause of failure.
In the conventional methods as described above, however, as the size of system logs or messages to be analyzed is increased, an overhead for finding the cause is increased. When a failure is repetitively taken place in several units relating to a single failure cause, there was a difficulty in systematically tracking the failure.